A threshold voltage of a driving TFT (Thin Film Transistor) of a pixel driving circuit included in a display device may be shifted due to process deviation, so as to cause non-uniformity in driving electric currents of various pixels. In a related art, a pixel driving circuit may not save space for a circuit design while eliminating threshold voltage deviation due to the process deviation. Accordingly, a pixel aperture ratio may not be readily increased and the number of signal lines may not be readily decreased, thereby resulting in a complex design and a high cost of the circuit.